Re: [PATCH v2 2/5] x86/idle: Disable IBRS when cpu is offline

[Waiman Long]

On 6/21/23 10:48, Peter Zijlstra wrote:
> On Wed, Jun 21, 2023 at 10:44:23AM -0400, Waiman Long wrote:
>
> > Well, hlt_play_dead() is only called if cpuidle_play_dead() returns an error
> > which is not the typical case. My testing does confirm that this patch is
> > able to keep the IBRS bit off when a CPU is offline via its online sysfs
> > file.
> The point is; your re-enable IBRS hunk at the end is dead-code. It
> should never ever run and having it is confusing.

What I meant is that hlt_play_dead() should never be called unless there 
is some serious problem with the system and native_play_dead() does 
return in normal usage.

Cheers,
Longman